1. Field of the Invention
This application is related to integrated circuits and more particularly, to integrated circuit charge pump voltage converters.
2. Description of the Related Art
In general, a charge pump circuit is a DC-to-DC voltage converter circuit that uses energy storage elements (e.g., capacitors) to increase or decrease a voltage level provided by a voltage power source. For example, a charge pump circuit may be used in an application that needs voltages greater than a power supply voltage level on a standard complementary metal-oxide-semiconductor (CMOS) integrated circuit. In some applications, different charge pump output voltage levels are needed at different times. Although a typical charge pump circuit can be designed to generate efficiently for a particular target output voltage or a narrow range of target output voltages, the typical charge pump circuit does not realize the same efficiency for a wide range of target output voltages. To generate multiple different target output voltages efficiently on-chip, a charge pump circuit for each target voltage level may be included on-chip. However, duplication of charge pump circuitry increases the area of the integrated circuit and may be cost-prohibitive. Accordingly, improved charge pump techniques are desired.